Terrestrial satellite transmitter systems are used for uplink signal transmissions in satellite communications. Generally, a satellite transmitter system includes an upconverter module that converts lower frequency modem data signals into higher frequency signals for an uplink signal transmission to a satellite and/or a power amplifier to increase the power of these higher frequency signals to levels adequate to reach the distant satellite with sufficient strength. Moreover, these transmitters are often referred to as a block upconverter (BUC) in the satellite communications industry, despite of the presence or absence of a power amplifier. This block upconverter is generally coupled with an orthogonal mode transducer that faces a parabolic reflector dish that is directed towards a specific satellite. Many times these block upconverters are used in portable satellite uplink systems. Furthermore, because conventional transmitter modules are constructed with many off-the-shelf components (i.e., a upconverter module, a power amplifier, a power supply, etc.), the casing and the chassis of a conventional transmitter module must be sufficiently large to house each off-the-shelf component. As a result, conventional transmitter modules include a rectangular (or square) cross sectioned form factor and are extremely heavy and cumbersome to carry and to set up, especially for use out in the field.
As consumers demand more data-rich media, satellite transmitter manufacturers are continually upgrading their products to handle higher uplink data-rate communication. However, in order to achieve these higher uplink data rates, the power requirements for uplink data signal transmission increases, together with the heat produced by the transmitter circuitry (e.g., a microwave power amplifier) are considerable. As these power levels increase, the conventional transmitter block upconverter modules with rectangular or square cross sections continue to grow, resulting in very large and heavy units that are inefficient at properly dissipating heat from the transmitter circuitry.
In addition to the demand for higher-power satellite transmitters capable of delivering higher data rates, consumers are also demanding that these transmitters be portable for mobile and quick-deploy applications. The importance of reducing the satellite transmitter's size and weight cannot be overstated for these portable applications.
Conventional satellite uplink transmitters include heat sinks with heat sink fins of equal height that are uniformly distributed across the surface area of the unit regardless of the location of the fins relative to the areas of greatest heat dissipation, resulting in a square or rectangular cross section. These heat sink fins of equal height utilized within a conventional transmitter block dissipate heat extremely inefficiently with regard to their size and weight, because the heat sink fins located at the areas of greatest heat levels generated by the transmitter circuitry are of the same height as the heat sink fins located at the lowest heat levels. These underutilized heat sink fins furthest from the areas of greatest heat levels add unnecessary weight and size to the overall block transmitter. This extra weight and size of these underutilized heat sink fins leads to higher material costs to build a conventional block transmitter and detracts from the portability of the unit.
Furthermore, because most air fans include rotating fan blades that form a circular cross section, managing the air flow within a rectangular cross section of a transmitter coupled with a circular cross sectioned air fan or fans is difficult and more costly. For example, using a circular fan that includes circular vanes and fan blades that form a circular cross section coupled with a rectangular-cross-section transmitter may lead to air flow distribution issues, air pressure differential issues, etc. To mitigate these issues and interface both the rectangular cross sectioned transmitter with the circular cross sectioned air fan, conventional transmitter designers have included a plenum chamber (i.e., an empty chamber) to help equalize air pressure within the unit for more even distribution of air flow. A similar issue occurs when using a row of several circular fans; a pressure-equalizing plenum is needed to ensure proper airflow across the heat sinking fins. However, utilizing one or more plenum, again, adds weight and volume to the transmitter unit.